ORGANOLEPTIC ANALYSIS OF OLIVE OIL

ORGANOLEPTIC ASSESSMENT METHOD OF NATURAL OLIVE OIL

1- Purpose and Scope

The purpose of this international method is to determine necessary criteria for assessing flavor characteristics of natural olive oil and to develop a methodology for classification.

2- Implementation Area

The method defines to a tasting group (tasters) chosen at a panel to identify what kinds of implementations will be made in determining classification of natural olive oil and rating deficiencies of olive oil according to intenseness, aroma (fruity flavor) and other positive attributes.

3- Glossary

3.1- Positive Attributes

Fruity: Set of olfactory sensations characteristic of the oil which depends on the variety and comes from sound, fresh olives, either ripe or unripe. If oil is made of unripe olives, aroma (perceived flavor) resembles green fruit. If the oil is made of ripe olives, aroma (perceived flavor) resembles both green and ripe (black) fruit.
Bitter: Characteristic primary taste of oil obtained from green olives or olives turning color. It is perceived in the papillae on the “V” region of the tongue.
Pungent:Biting tactile sensation characteristic of oil produced at the beginning of the season, primarily from olives that are still unripe. It can be perceived throughout the whole mouth, particularly in the throat.

3.2- Negative Attributes

Fusty-Muddy Sediment: Characteristic negative flavor and taste of oil made of olives piled or stored in such conditions as to have undergone an advanced stage of anaerobic fermentation, or which has been left in contact with the sediment that settles in underground tanks or vats and which has also undergone a process of anaerobic fermentation.

Musty-Humid: Characteristic negative flavor and taste of oil obtained from fruits, which have been stored in humid conditions for several days, where as a result large numbers of humid fungi and yeasts have developed on it. .

Winey-Vinegary: Characteristic taste of certain oil with resembling wine or vinegar. This vinegar flavor is mainly due to a process of fermentation in the olives which leads to the formation of acetic acid, ethyl acetate and ethanol. The reason of this flavor is aerobic fermentation of the olives or olive paste left on pressing mats which have not been properly cleaned..

Metallic : Taste resembling metals. It is characteristic of oil which has been in prolonged contact with metallic surfaces during crushing, mixing, pressing or storage.

Rancid-Oxidized: lavor of oil which have undergone an intense process of oxidation (aerobic).

Heated or Burnt-Burned: Characteristic taste of oil caused by excessive and/or prolonged heating during processing. It is particularly seen when the paste is thermally mixed, especially if this is done under unsuitable conditions.

Hay-Wood: Characteristic taste of oil made of dried olives.

Crude-Rough-Raw: Thick, pasty mouthful sensation created by certain old oil.

Greasy: Negative flavor and taste of oil resembling diesel oil, grease or mineral oil.

Residual Water: Flavor and taste of oil as a result of prolonged contact with residual water of olives which has undergone (exposed to) fermentation processes.

Brine: Flavor and taste of oil extracted from olives which have been preserved in brine.

Espartograss (Mat-Linen Sack): Characteristic negative flavor and taste of oil results from olives pressed in newly produced espartograss mats. This flavor and taste may vary depending on whether the mats are made of green or dried espartograss.

Earthy: Negative flavor of oil results from olives which have been collected with earth or mud and not being washed.

Grubby: Negative sweet flavor of oil results from olives which have been severely attacked by the worms of the olive fly (Bactrocera oleae).

Cucumber: Cucumber-like negative taste and spongy texture produced when oil is hermetically packed for too long in tin containers and which is attributed to 2, 6 nonadienal formation.

Wet Wood: Negative flavor of oil extracted from olives which have been frozen on tree.

3.3- Optional Terminology for Labeling Purposes

Upon request, the panel leader may certify that the oil that comply with the definitions and sets corresponding to the following adjectives according to the intensity and perception of the attributes.

A- Each positive attribute stated in Clause 3.1 (fruity – ripe or unripe, pungent and bitter):

(i) Intense title (adjective) can be used when median (medium value) characteristic is more than 6.
(ii) Medium (average) title (adjective) can be used when median (medium value) characteristic is between 2 and 6.
(iii) Light title (adjective) can be used when median (medium value) characteristic is less than 3.
(iv) If specifications require median (medium value) characteristic to be 3 or more, it can be used without the adjectives stated in subparagraphs (i), (ii), (iii).

B- Balanced (Compatible) Adjective: It can be used in such cases when flavor, taste and sensation of oil do not indicate a lack of balance and the median of the bitter and/or pungent attributes is 2 points higher than the median of the fruitiness.

C- Mild Soft Oil (It is necessary to differ it from light) (Sweet Oil): It can be used in such cases when the median of the bitter and pungent attributes is 2 or less.

4- Panel

A panel is composed of a panel leader and 8-12 tasters.

The panel leader should be an expert who is sufficiently trained on the oil varieties that will be tested in the panel. The panel leader is responsible for organization and performance of the panel as well as preparation, numbering, presentation to the tasters, collection and data processing of the samples.

The panel leader trains the tasters and evaluate whether their performance complies with the standards.

The tasters should be evaluated according to their abilities to distinguish the differences between similar samples. Taster training certificate is granted to the people who are successful at the end of the training by the International Olive Oil Council.

Panel should have national qualification and it should be a social and international organization of organoleptic assessment for harmonizing the purpose of learning period and organoleptic criteria. Panels should comply with Section 4 of this Article.

5- Procedure for Organoleptic Assessment and Classification of Natural Olive Oil

5.1- Use of profile sheets by the tasters

The profile sheet which is aimed to be used by the tasters is detailed in Figure A of the method.

Each taster on the panel shall sniff and then taste the oil contained in the tasting glass in order to analyse the olfactory, gustatory, qualitative retronasal, tactile and kinaesthetic sensations 1/; and then the taster shall enter the intensity of each descriptor of positive and negative characteristics perceived onto the profile sheet provided for this purpose. When the taster perceives fruitiness as ripen or unripen, the taster shall check the box corresponding thereto on the profile sheet.

If the taster perceives any negative characteristics that have not been provided on the profile sheet, the taster shall record these under the title of ‘‘others’’ by using the most appropriate definitive term or terms that are stated in Section 3.2 of the method.

5.2- Use of data by the panel leader

The panel leader shall collect the profile sheets completed by each taster and shall review the intensities recorded. If the panel leader finds any anomaly, the panel leader shall invite the taster to revise his profile sheet and, if necessary, to repeat the test.

Panel leader shall enter data of each taster into a computer program that accompanies the method with an approach for obtaining statistical calculations (median). Data regarding a certain sample shall be entered by using a matrix which consists of 9 columns representing 9 organoleptic characteristics and n rows representing n taster.

If a negative attribute is entered under the title of “others” by at least 50% of the panel participants, the panel leader shall calculate median of the negative attribute and shall conclude to the corresponding classification.

As the result of at least 50% of the tasters perceive the oil used in the test as green and ripe terms for fruity characteristic stated in 3.3(a), attributes of the oil can be approved and confirmed by the panel leader.

A test should definitely be made in assessments for compliance control. If there are contradictious assessments, the panel leader should organize a second assessment. The assessment should be made for the third time for confirming the assessment. In such a case, median of the characteristic should be calculated over averages of the medians. Repeated tests should be made in different sessions.

5.3- Grading Oil

The median of negative attributes and the median of fruitiness are graded as in the followings. The median of the most intensively perceived negative attributes is determined as the median of negative attributes. The median of negative attributes and fruitiness are given as a decimal number and the constant coefficient of variation should not be more than 20%.

Oil is graded by comparing the median of negative attributes and the median of fruitiness according to below mentioned reference ranges. The error of the calculated method should be taken into consideration for reaching a precise result when limits of these ranges are determined. In computer programs where statistical table and graphic are used may help you to visualize grading.

A- Extra Virgin Olive Oil: The median of negative attributes is 0 and the median of fruitiness is over 0.

B- Ordinary Virgin Olive Oil: The median of negative attributes is between 0 and 3.5 and the median of fruitiness is over 0.

C- Lampante Virgin Olive Oil: The median of negative attributes is 3.5. Even if the median of negative attributes is over 3.5, the median of fruitiness is 0.

5.4- Special Condition

If the median of other positive attributes are more than 5, which is the median of fruitiness, the panel leader should indicate this value on the certificate of analysis.

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